Should you repair or replace your roof?
How to tell whether a repair will hold or the roof has had its time, from a roofer who does both across Oxford and Oxfordshire.
Free roof surveys with a written report
Repair your roof if the problem is in one place and the felt, battens and timbers underneath are still sound; replace it when faults are spread across the whole roof, the felt has failed, or repairs keep coming back. A tired-looking roof often needs only a repair, and a tidy one can be failing underneath.
When a roof repair is enough
A repair makes sense when the damage has one clear cause and the rest of the roof is doing its job: a few tiles slipped or blown off, loose ridge tiles where the mortar has washed out, a split flashing, or a valley blocked with moss.
The test is what's underneath. If the felt in the loft is whole, the battens are firm and there are no stains elsewhere, fixing the one fault should give the roof years more life. See roof repairs for the repairs themselves.
There's a middle way too: re-roofing just one slope, often the back.
Signs a roof needs replacing
One fault is a repair. Several of these at once usually mean the roof is near the end:
- Tiles slipping all over a slope: the nails or battens are failing (nail sickness).
- Felt torn, sagging or missing in the loft.
- Daylight through the tiles from inside.
- Leaks in different places, or the same leak back after a repair.
- Concrete tiles worn rough, holding moss, with grit washing into the gutters.
- A dip along the ridge or a sagging slope: get that looked at soon, as the timbers may have moved.
You can check most of this without going up a ladder:
Look from the street
On a dry day, look along the ridge and the slopes. Look for gaps, odd-coloured tiles and dips.
Go into the loft on a sunny day
Turn the light off and look for pinpricks of daylight. Step only on the joists.
Look at the felt and timbers
With a torch, check the felt for tears and sagging, and the timbers for dark stains or soft patches.
How long roofs last in the UK
A roof lasts as long as its weakest layer, and that's rarely the tiles. Nails rust, battens rot and old felt goes brittle long before a good tile or slate wears out. These are typical trade figures, not promises: exposure, pitch and workmanship change them.
Around Oxford, the age of the house is a good first clue. The 1930s semis in Headington, Cowley and Marston are nearly 90 years old, so it's worth knowing whether yours has been re-roofed before. Many post-war houses in Rose Hill, Barton and Blackbird Leys have concrete interlocking tiles. The Victorian terraces in Grandpont and East Oxford are often slate, and old slate roofs often have sound slates on failing nails. Flat roofs are different: see flat roofing.
| Typical life | What usually fails first | |
|---|---|---|
| Concrete interlocking tiles | Often 50 years or more | The surface wears porous; ridge mortar cracks |
| Clay plain tiles | Often 60 to 100 years | Nails and battens; frost flakes the tile faces |
| Natural slate | Often 100 years or more | Nails rust and the slates slip |
| Fibre-cement slate | Often around 30 years | Slates curl and the coating wears |
| Old bitumen roofing felt | Often 30 to 40 years | Goes brittle and tears, first at the eaves |
What affects the cost of repairing or replacing a roof
I don't publish prices, because two roofs that look alike can be very different jobs. Every job is priced after I've looked at it, and the quote is free and in writing. What moves the cost:
- Size, shape and pitch: a hipped roof means more cutting than a simple gable.
- Access and scaffolding: a re-roof needs scaffolding all round; a small repair often doesn't. I arrange it, and it's in the quote.
- The tiles: plain tiles need far more tiles and battens per square metre than interlocking ones.
- What's underneath: rotten battens or rafters only show once the roof is open. If I find more work then, I talk it through with you first.
- The edges: chimneys, flashings, valleys and gutters needing work at the same time.
The real comparison is over time. A third or fourth repair on a failing roof can add up to a good part of a new one, without the new felt or the long guarantee.
Get the roof looked at before you decide
From the ground you can spot warning signs, not what's under the tiles. The felt, battens and fixings decide whether a repair will last, and they only show from close up. I offer free roof surveys with a written report: I look at the roof in person, and the report, sent by email, lists all the work the roof needs.
If a repair will do the job, I'll tell you so. See roof replacement for what a full re-roof with me includes.
Repairing or replacing a roof, side by side
| Repair | Replace | |
|---|---|---|
| Best when | The damage is in one place and the rest is sound | Faults are all over the roof, or the felt has failed |
| What's done | Tiles, ridge, flashing or valley fixed where needed | Stripped to the rafters, new membrane, battens and tiles |
| The felt underneath | Stays as it is | Replaced with breathable membrane |
| Cost | Less now, but repeat repairs add up | More at once, then little to spend for years |
| My written guarantee | At least 5 years | 20 years on a new roof |
Repair suits one clear fault with sound felt and timbers. Replacement suits a roof that leaks in several places, slips tiles across whole slopes or has torn felt. A free survey settles it.
Questions about repairing or replacing a roof
Should I repair or replace my roof?
Repair it if the fault is in one place and the felt, battens and timbers are still sound; replace it if problems are spread across the roof or keep coming back. Age alone doesn't decide it: an old slate roof may need only new fixings, while a younger roof with failed felt may need stripping.
What are the signs a roof needs replacing?
The main signs a roof needs replacing are tiles slipping across a whole slope, torn or missing felt, daylight through the tiles, leaks in more than one place, worn concrete tiles and a dip in the ridge. One of these alone may be a repair. Several together usually mean the roof is at the end of its life.
How long do roofs last in the UK?
Most UK pitched roofs last 30 to 100 years, depending on the covering. As a rough trade guide, concrete tiles often last 50 years or more, clay plain tiles 60 to 100, and natural slate 100 or more. The fixings and felt usually fail first, so a roof can need work while the tiles look fine.
Related pages
Slate roofing
On old slate roofs it's often the nails that give up, not the slates.
Roof leak repair
Water already coming in? Start by finding where it gets in.
Not sure what your roof needs?
A photo on WhatsApp is enough to start. I usually come and look the next day and tell you whether a repair will do. The survey and the quote cost nothing.
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